It is known to apply a wetting agent to a tooth preparation prior to the taking of an impression with hydrocolloid impression materials, such as polyethers. In recent years the use of hydrocolloids has decreased in favor of vinyl polysiloxane, silicone or other rubber or elastomeric impression materials. A drawback to the use of these dental impression materials has been their hydrophobicity, making it difficult to take precise impressions of the details of the tooth and/or hard tissue when it is wetted with blood, saliva, or other fluids. When making the impression, the blood, saliva, or other fluids are forced into the margins of the teeth or pits and fissures in the teeth by the hydrophobic silicone impression material, rendering it difficult to take detailed and precise impressions because of the high surface tension of the materials. The dental practitioner may attempt to dry the oral cavity by blowing air into the oral cavity, but this is cumbersome not only for the practitioner but also the patient, particularly where the patient is bleeding. The hydrophobicity of dental impression materials also prevents the formation of accurate models formed from gypsum slurries.
Repeated attempts have been made to render silicone dental impression materials more hydrophilic by including various ionic or non-ionic surfactants in the composition, as is described, for example, in DE 4129613 to Hefner et al., U.S. Pat. No. 4,657,959 to Bryan et al., U.S. Pat. No. 4,691,039 to Aasen et al., and U.S. Pat. No. 4,752,633 to Aasen et al. U.S. Pat. No. 4,778,832 to Futami discloses use of a protein additive, such as albumin, as well as a silicone oil or non-ionic surfactant to increase hydrophilicity. While these materials have met with some success, the additives sometimes suffer from certain drawbacks, including instability in moist air, deactivation of platinum catalyst complexes, and reduction in the tear strength of the dental impression. For example, they may swell first in water, and then dissolve gradually, and undergo phase separation, such as in vinyl-termimated polydimethylsiloxane base components.
U.S. Pat. No. 5,534,560 describes an attempt to modify the impression material rather than wetting the dentition. As such, this patent describes a variation of the prior art that involves changing the chemistry of the impression material to make it less hydrophobic.
A need exists therefore, for a method of preparing or conditioning dentition to receive or physically contact a dental impression material in order to affect a detailed and accurate impression. That is, the need exists for a material that will wet the dentition as opposed to modifying the impression material. The method should be useful with both hydrophobic and hydrophilic dental impression materials. The method should also be useful in assisting the practitioner in removing the impression material from the dentition.